You are not alone in this decision. I am a fellow Class of 2019er who just turned down Stanford for Pomona. Although my interests are quite different from yours, I strongly believe that the value of a liberal arts education is universal. Small classes, devoted teachers and a responsive administration are pretty clearly positive things.
Stanford is obviously also an incredible place, but in the end, will you really have a better four years there? I certainly would not have. I urge you to ignore the opinions of others when making your decision. Name recognition certainly matters, but it is not everything. College is more than just a means to an end: It is a destination in and of itself.